A MODEL OF POTENTIAL MAIZE YIELD IN RELATION TO ACCUMULATED TEMPERATURE AND ITS APPLICATION IN ASSESSING THE IMPACT OF CLIMATIC CHANGE

Plant breeding for different maturities plays an important role in agricultural strategies for adaptation to climaticchange.In this paper using the data of ten corn hybrids with early,medium and late maturities and different leaf angles,including erectophile and planophile,observed in Beijing,Yanqing,Tai'an,Gongzhuling of Jilin and Shihezi ofXinjiang,a normal growing function was derived on the basis of the main pattern of accumulated dry matter:W=1/1+exp(8.56-13.52u)In accordance with the function authors built up a model of potential maximum biomass which depends on accumulatedtemperatureB_(max)=100+1.11∑~T_m(kg/mu)(1ha=15mu)The model was applied to estimate the potential corn yield of hybrids with different maturities,and applications ofthe results in assessing the impact of climatic change are discussed.     

中国金矿床分布的分形研究

根据1:40O万中国岩金成矿图,在矿床地质研究基础上,用分形理论探讨了中国岩金矿的空间分布。研究表明,在两个尺度范围内,金矿床在空间上呈分形分布,其中数盒子法的分维数D分别为0.3333(5～80km)和1.3259(80～2400km);密度分布的分维数D分别为1.2033(5～80km)和1.5459(80～2400km)。金矿床的分形分布给超大陆旋回会聚构造边缘控制金矿的分布及成矿作用的观点以有力的佐证。     

火成岩构造组合与壳-幔成矿系统

讨论了火成岩构造组合,指出不能单纯地运用化学图解,强调要结合岩相学、岩石组合特征研究,要注意区分区域与局部的构造环境。指出双峰式火成岩组合的确切含义是指缺乏中性成员,而不单看化学图解的几何形态,讨论了伸展与挤压对双峰式和钙碱性火成岩组合的可能约束。指出由蛇绿岩套再造的古构造历史可能是残缺的,结合弧火成岩的厘定可在某些方面弥补这个不足,讨论了弧火成岩组成极性形成的可能原因。讨论了大陆碰撞造山带的火成岩构造组合类型及其在再造造山带的边界性质、造山带演化历史中的重要意义。指出大陆裂谷带的火成岩常呈组成对称的水平分带,而不同于弧火成岩的组成极性。讨论了岩浆构造热事件及其序列的重要意义,提出大陆碰撞造山带具类似于变质作用的顺时针演化的事件序列,而大洋俯冲造山带则具反时针演化的事件序列。最后,强调并讨论了“壳幔岩浆流体成矿系统”的科学命题,提出从壳幔这个大系统来考察成矿作用是很重要的     

Carbon dioxide emissions from the Three Gorges Reservoir,China

Carbon dioxide (CO₂) emission from the river-type reservoir is an hotspot of carbon cycle within inland waters. However, related studies on the different types of reservoirs are still inadequate. Therefore, we sampled the Three Gorges Reservoir (TGR), a typical river-type reservoir having both river and lake characteristics, using an online system (HydroCTM/CO₂) and YSI-6600v2 meter to determine the partial pressure of carbon dioxide (pCO₂) and physical chemical parameters in 2013. The results showed that the CO₂ flux from the mainstream ranged from 26.1 to 92.2 mg CO₂/m² h with average CO₂ fluxes of 50.0 mg/m² h. The CO₂ fluxes from the tributary ranged from ?10.91 to 53.95 mg CO₂/m² h with area-weighted average CO₂ fluxes of 11.4 mg/m² h. The main stream emits CO₂ to the atmosphere the whole year; however, the surface water of the tributary can sometimes act as a sink of CO₂ for the atmosphere. As the operation of the TGR, the tributary became more favorable to photosynthetic uptake of CO₂ especially in summer. The total CO₂ flux was estimated to be 0.34 and 0.03 Tg CO₂/year from the mainstream and the tributaries, respectively. Our emission rates are lower than previous estimates, but they are in agreement with the average CO₂ flux from temperate reservoirs estimated by Barros et al. (Nat Geosci 4(9):593–596, 2011).     

Space/Time Features of the Secular Variation in 1951–1998 Northern 500-hPa Height

Summary  This paper presents a trend coefficient as a characteristic index with which to investigate the 1951–1998 secular trend variation (STV) of northern 500-hPa height on a seasonal basis. Evidence suggests that low (high) latitude 500 hPa geopotential height displays a remarkably positive (negative) trend; the positive anomaly of the height is maintained over NW Africa, the western Mediterranean Sea and North Africa, mid-Pacific at lower latitudes, Lake Baikal and area to the east and NW North America; the height drops significantly over the Aleutians and North Pacific, the area to the south of the Greenland and NE North America and the sector to the north of the Arabian Sea. Further, analysis of abrupt change shows that the 500-hPa circulations experience noticeable sudden change twice, once around the early 1960s and again in 1976, during which period the height exhibits great differences between the Pacific and Atlantic. In the first period it drops (rises) over the mid-Atlantic at lower latitudes (NW Africa); in the second period the height rises (drops) over the mid-Pacific at lower latitudes and Lake Baikal (the North Pacific). Statistical tests indicate that in the 1976 case the low-latitude positive abrupt change is even more noticeable compared to the negative of the North Pacific, thus representing a large-scale jumping event of the northern 500-hPa height. Received April 9, 1999/Revised October 15, 1999     

Advances in terrestrial system research in China

Land surface is of spatial-temporal heterogeneity. Terrestrial system (TS) comprehensively studies on land surface and physical regionalization objectively describes geographical zonation of the system. China has a vast area with apparent spatial variations in resources and environmental conditions, which highly influence on socio-economic development. In this paper, progress of the TS studies in China is overviewed and research priorities in the near future are prospected. Since the 1950s, China has paid great attention to the TS study as its socio-economic development, and conducted research on physical geographical regionalization, eco-geographical regionalization and comprehensive regionalization. Along with the deepening of global change research, dynamics of TS have been highly concerned. During the studies, methodology has been developed from qualitative research of integration of experts’ brainpower gradually to quantitative research based on field observation and experiments of the natural processes, including physical, chemical and biological processes, as well as application of information technology and mathematical simulation. In the near future, TS would combine with the ideology, objectives and key researches of Future Earth program, to focus on the mechanism and regional effects of interaction among land surface elements, the response of TS to global change, the quantitative recognition on regional unit boundary, and the application to TS in sustainable socio-economic development.     

我国汛期降水的EOF分析

本文选取了均匀分布的32个测站作为研究对象,取其1951—1985年汛期(4—9月)的逐月降水量,利用经验正交函数(EOF)分析方法对我国汛期降水的基本气候特征进行了研究。分析表明,所得到的各特征向量场及其对应的时间系数很好地代表了我国汛期降水的空间分布和时间变化(包括季节变化和年际变化)。这些结果为我们进一步探讨海温场、高度场等物理因子与我国汛期降水型的关系提供了基础。     

‘Qianzhong Uplift’ and evolution of the Late Paleozoic palaeogeography and its control on formation of bauxite in Guizhou Province

The Early Paleozoic regional uplift(e.g.,the Qianzhong Uplift)and sea-level changes had obviously controlled the evolution of the Late Paleozoic palaeogeography and paleogeomorphology in Guizhou Province. However,the formation time and evolution of the Qianzhong Uplift is still in debate,which limits the understanding of the Permo-Carboniferous paleogeographic and paleogeomorphologic evolution that formed bauxite in Guizhou. In this paper,based on field surveys and data collection,we established the palaeogeography of several important geological periods from the Late Cambrian to Permian in Guizhou,and re-recognized the formation time and evolution of the Qianzhong Uplift,and revealed the coupling relationship between the Qianzhong Uplift and Guizhou bauxite formation. During the Cambrian to early-middle Early Silurian,the continent-marine transitional facies were missed in the northern margin of the Qianzhong Uplift,central Guizhou Province,such as Bijie,Jinsha and Zunyi. The large-scale uplift of the central Guizhou Province should begin with the tidal flat deposits of the Hanchiatien Formation in the Early Silurian. Because of the Qianzhong Uplift,the central Guizhou and Zunyi areas experienced long-lasting and intense weathering and erosion,forming karst depressions,funnels,and canyons in the Early Carboniferous. The karst landform provided material conditions and location for the formation of bauxite deposits in the Early Carboniferous. The bauxite ore formed under intense chemical wreathing and leaching induced by the glacio-eustasy and paleoclimate fluctuations. The early long-lasting and intense weathering and erosion occurred in the northern Guizhou along with the Permo-Carboniferous glacio-eustasy,had leaded to the formation of coastal wetland and depressions,which were favorable places for the Early Permian bauxite formation. The Early Permian bauxite ores in Guizhou Province have an obvious coupling relationship with the Late Paleozoic Ice Age.     

拖拉机驾驶机器人设计及人机协作方法研究

针对农用拖拉机智能化程度低,以及现有的人工智能水平尚无法完全实现自主驾驶控制拖拉机等问题,本文设计一种基于人机协作的拖拉机驾驶机器人.拖拉机驾驶机器人可以对拖拉机进行快速、无损、智能化升级,其结构由转向控制机械手、换挡机械手、旋耕机升降控制机械手和踏板控制机械腿等组成.通过研究人机协作的控制方法,提出了人机协作介入准则和基于转向电机电流反馈扭矩检测的人机协作模式切换方法,研制了原理样机验证拖拉机驾驶机器人的可行性和人机协作控制策略的有效性,对促进精准农业,提高现代农业智能化装备水平具有重要的现实意义.     

Crust-Mantle Structure and Coupling Effects on Mineralization： An Example from J iaodong Gold Ore Deposits Concentrating Area, China

Based on the results of two-dimension velocity structure, 1 : 100 000 aeromagnetic anoma-ly, 1 : 200 000 bouguer gravity anomaly and seismic anisotropy of Jiaodong and neighboring region in Shandong, China, the information of geophysical field was divided into two parts: deep- and shallow-focus fields. And then, the information of two different fields was combined with that of deep-seated ge-ology and ore deposit features. The synthetic result was adopted to analyze three-dimension structure, to probe into crust-mantle coupling effects of mineralization and dynamics of ore formation system.